Preparation of organomercury compounds



iinited States harem 2955030? Patented Aug. 23, 1960 the prior artprocesses and dry materials are not required. A further advantage isthat a very simple re- 2,950,303 covery system is accomplished with theproduct usually being readily withdrawn from the reaction system asgggggi ggg 5 formed permitting ready adaptability of the process tocontinuous operation. A still further advantage of the James M. Riddle,Baton Rouge, La., assignor to Ethyl process is that the oxide oreitself, which is readily avail- Corporation, New York, N.Y., acorporation of Deiaable and economical, can be employed. Still other ad-Wfil'e vantages will be apparent.

No Drawing. Ffied May 1 1959 Sen No. 810,236 While any form of an oxideof mercury is applicable in the process of this invention, mercuric andmercurous 4 Ciaims. (Cl. 260-431) oxide or the ore itself (montroydite)are generally employed. Mercuric oxide is preferably used along withmontroydite because of their greater availability and The presentinvention is concerned with a process for easier handling- When Suchmaterials are not Soluble the production of organomercury compounds,particuin the reaction system, they can be employed in massive larlydialkylmercury compounds. form. Generally, however, it is convenient touse these There are numerous methods reported in the literature m trials as finelydivided parti les below about A" in for the preparationof organomercury compounds. Withmajor dimension with particles below inmajor out attempting to mention all such processes, the follow- 20dimension being preferred for easier handling and faster ing aretypical: mercury has been reacted with alkyl reaction rates. halides toform alkyl mercury halides; sodium amalgam The organoborane compoundsemployed in the prochas been reacted with alkyl halides to formdialkyless are the trialkylor trialkenylboranes. In g n r mercurycompounds; and certain mercury halides have such compounds will containup to and including about been reacted with certain organometalliccompounds, 18 carbon atoms in each hydrocarbon portion. Illustrae.g. theGrignard reagent, to form the dialkyl mercury tive examples of thealkyland alkenylboranes are tricom-pounds. All of the presently knownprocedures are methylbmane, 'ffie'ihylbol'afle, iTiPIOPYIbOIaIIB, yprimarily of academic interest and sufier particulardisborane,trioctylborane,tridecylborane, tridodecycloborane, advantages.So far as now known, a simple and contrioctadecylborane, trivinylborane,tri-l-propenylborane, venient method for the preparation ofdialkylmercury tri-2-butenylborane, tri-l-hexenylborane,tri-l-octenylcompounds, readily adaptable to commercial operation,borane, tri-l-octadecenylborane, tri-2,4-octadecadienylhas not beenavailable. borane and the like. It is to be understood that the hydro-The alkyl mercury compounds are of considerable carbon portions of suchcompounds can be branched utility. For example, they are useful asintermediates chain and further substituted with functional groups forforming other organometallic compounds, a typical which are essentiallyinert in the reaction, such as the reaction being that of diethylmercurywith sodium metal halogens, carbonyl and the like. The trialkyland tritoform ethylsodinm. Another use for the mercury comalkenylboranes of thelower alkyl and alkenyl radicals, pounds, and derivatives thereof, is inagricultural chemthat is, having up to and including about 8 carbonatoms ical applications. Still other uses are known and a in each ofsuch groups, are preferred because of their more practical method fortheir preparation is desirable greater availability and reactivity inthe process. The to further amplify the utility of these compounds.trialkylboranes having up to and including about 8 car- Accordingly, anobject of this invention is to provide bon atoms in each alkyl group aremore especially prea new and novel process for the production oforganoferred, particularly triethylborane, because of their easiermercury compounds. A further object is to provide a handling and greateravailability. process whereby greater and more economical yields of Theproportions of the reactants can be varied over a organomercurycompounds are obtained. A particular considerable range to result in thedesired organomercury object is to provide a new and novel process forthe manucompound. It is preferable, however, to employ at least factureof dialkylmercury compounds. These and other the stoichiometric amountof the alky or alkenylborane objects will be apparent as the discussionproceeds. compound. Advantage is achieved in higher yields and The aboveand other objects of this invention are faster reaction rates when amolar excess between about accomplished by reacting a trialkylortrialkenylborane 5 to 15 percent of the alkylor alkenylborane isemployed. with an oxide of mercury in an aqueous medium. Mercu- Indetermining the stoichiometry, one can base it upon the ric oxide is thepreferred oxide of mercury and the lower consumption of one or all ofthe alkyl or alkenyl groups trialkylboranes are the preferredorganoborane comin the trialkyland trialkenylboranes. Since fasterreacpounds, especially triethylborane. Particular advantage tion isobtained of the first alkyl or alkenyl group of the is achieved when thereaction is conducted at a temperorganoborane compound, a particularembodiment of the ature between 20 to 100 C. and enough water isinvention comprises employing the above stoichiometric present toprovide a fluid reaction mixture. Still furportions based upon reactionof only one alkyl group per ther advantage in improving the basicreaction is obmolecule of the alkylor alkenylborane. The water emtainedwhen an alkali metal hydroxide, particularly so ployed in the system isusually provided in amount to resodium hydroxide, is incorporated in thereaction mixsult in a fluid reaction mixture. It is also desirable toemture in at least minor amount. Thus, a particularly ploy at least 3moles of water per mole of the trialkylpreferred embodiment of thisinvention comprises the or trialkenylborane. In a preferred embodiment,bereaction of mercuric oxide with a lower trialkylborane tween about 5to 200 moles of water per mole of the alkylat a temperature betweenabout 20 to 100 C. in the or alkenylborane is employed. presence ofsuflicient water to provide a fluid reaction The process is subject torelatively simple manipulative system. A still more preferred embodimentcomprises operations. In general, the requisite amounts oforganoconducting the latter reaction in the further presence boranecompound and water are added to a reactor and of at least a minor amountof sodium hydroxide. then the mercury oxide is added thereto. Thereverse The present invention is of particular advantage in mode ofaddition is equally applicable although higher that high yields,essentially quantitative, are obtained at yields are obtained whenadding the oxide to the organoless stringent and under less hazardousconditions than borane. The mixture is then agitated to facilitatecontact of the reactants. During the addition and reaction, an inertatmosphere, such as argon, nitrogen, or krypton, is preferably employedbecause of the flammability of the organoborane'compoundJ The mixture isreacted at the desired temperature and then, or during the course of thereaction, the product can be withdrawn in essentially pure form from thebottom of the reactor, in those instances wherein the product is ofappropriate specific gravity, or, alternatively, the product is readilydistillable from the reaction mixture in pure form. It is to beunderstood that other variations in the process can be made withoutdeparting from the purposes of the present i-nven tion.

The process will be more completely understood from a consideration ofthe following examples wherein all parts are by weight unless otherwisespecified.

7 Example I To a reactor equipped with internal agitation, externalheating means, a reflux condenser, and a means for maintaining an inertatmosphere, is added 105 parts of triethylborane and 1000 parts of waterunder a nitrogen atmosphere. Agitation is commenced and the mixture isheated to 50 (3. Then 325 parts of mercuric oxide of particle size belowin diameter is added thereto over a period of minutes. Two colorlesslayers immediately form. The diethylmercury is withdrawn from the 7bottom of the reaction mixture in high yield.

Example II Example Ill When Example 1 1 is repeated substitutingtrioctylborane for triethylborane with the reaction temperature at 80 C.and adding the mercuric oxide to a solution of the borane and sodiumhydroxide in the water, dioctylmercury is readily withdrawn from thebottom of'the reactor in essentially quantitative yield.

Example 1V When trivinylborane is reacted with mercurous oxide employinga 5 percent excess of the trivinylborane in the presence of moles ofwater per mole of the borane and 0.1 moles of potassium hydroxide permole of the borane at room temperature, divinylmercury is obtained.

Example V Employing the procedure of Example I, di-l-hexenylmercury isobtained in highyield when tri-l-hexenylborane is reacted with mercuricoxide at 50 C. for /2 hour.

Example VI 7 When 0.58 mole of tri-l-octadece'nylborane are reacted with0.25 mole of mercuric oxide in the presence of 10 moles of water and0.012 mole of calcium hydroxide at a temperature of 100 C.,di-l-octadecenylmercury is obtained.

Example VII Employing the procedure of'Example VI, when finely dividedmercuric oxide is added to a solution of triocta- 'decylborane in waterand containing a minor amount of 7 sodium hydroxide while maintainingthe reaction mixture at C. during addition, dioctadecylmercury can becontinuously withdrawn from the bottom of the reactor in high yieldduring the course of addition.

The above examples are presented by way of illustration and theinvention is not intended to be limited thereby. It will be evident thatother organoborane compounds described hereinbefore can be substitutedto. produce similar results.

As indicated, advantage is achieved by incorporating a base in thereaction mixture. The incorporation of such materials in the reactionmixture enhances the yields obtained and provides more eflficientseparation of the organomercury product. For this purpose the alkali andalkaline earth hydroxides are quite well suited as, for example, sodiumhydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide,calcium hydroxide, strontium hydroxide, and the like. The hydroxide needbe added only in minor amount to result in a slight basicity of thereaction mixture. Generally, such materials are preferably added inamount between about 0.1 to 3.0 moles of hydroxide ion per mole of themercury oxide.

The temperature at which the reaction is conducted is subject toconsiderable latitude, but generally is between about 0 C. to thedecomposition temperature of'the reactants or products. For practicalreasons, the reaction is ordinarily conducted 'at between about 0 to C.Best results are obtained, however, when the temperature is maintainedbetween 20 to 100 C. There is no need to employ pressure in theoperation unless one desires to conduct the reaction at a temperatureabove the boiling point of the reaction mixture. Reduced pressures canbe employed if it is desired to steam distill the product from thereaction mixture as, for example, when it is lower boiling than theorganoborane reactant.

The reaction is generally instantaneous so that time is not a criticalfactor. That is, the reaction is essentially complete upon completion ofaddition of the mercury oxide to the alkylor alkenylborane or viceversa. The time of addition can vary from between about 5 minutes to 2hours or longer, although addition periods of about 30 minutes areusually quite adequate. Because of the instantaneous reactivity and theready removal of the product from the reaction system, the process isreadily adaptable for continuous operation. 'For example, one suchoperation would be the co-mingling of the mercuric oxide with a streamof the trialky-l-or trialkenylborane, water, and hydroxide, if employed,with continuous separation of the organomercury product from the system.

Having thus described the process of this invention, it is not intendedthat it be limited except as set forth in the following claims.

I claim:

1. A process for the manufacture of mercury products selected from thegroup consisting of alkyland alkenylmercury compounds which comprisesreacting an organoborane selected from the group consisting oftrialkyland trialkenylborane with. an oxide of mercury in the presenceof water.

2. A process for the preparation of diethylmercury which comprisesreacting mercuric oxide with triethylborane at a temperature betweenabout 20 C. to 100 C. in the presence of water and in the furtherpresence of a minor amount of sodium hydroxide.

3. The process of claim 1 wherein said organoborane is a trialkylborane,said oxide of mercury is mercuric oxide, and said reaction is conductedat a temperature between about 20 to 100 C.

4. The process of claim 3 further characterized in that the reaction isconducted in the presence of a hydroxide selected from the groupconsisting of alkali and alkaline earth metal hydroxides.

No references cited.

1. A PROCESS FOR THE MANUFACTURE OF MERCURY PRODUCTS SELECTED FROM THEGROUP CONSISTING OF ALKYL- AND ALKENYLMERCURY COMPOUNDS WHICH COMPRISESREACTING AN ORGANOBORANE SELECTED FROM THE GROUP CONSISTING OF TRIALKYL-AND TRIALKENYLBORANE WITH AN OXIDE OF MERCURY IN THE PRESENCE OF WATER.